Orthopaedic surgical procedures, particularly shoulder arthroscopy, have continued to grow very rapidly. In North America, more than 150,000 procedures are performed yearly, mainly as a result of sports-related injuries. In the U.S. alone there are over 13,000 active, board-certified orthopaedic surgeons engaged in the full- or part-time practice of orthopaedic surgery. Of these, according to data from the American Academy of Orthopaedic Surgeons, more than 25% concentrate on shoulder and elbow procedures. This significant growth is mainly attributed to changes in the procedures themselves, the most significant being arthroscopic surgery. In the past, treatment of orthopaedic injuries involved extensive surgery, including large incisions, and a prolonged recovery period. With the help of an arthroscope, the orthopaedic surgeon can easily examine, diagnose, and treat problems in the joint that previously may have been difficult to identify.
Generally, shoulder procedures are performed with the patient under general anesthesia, lying in the lateral decubitus position, with the arm in traction to distend the shoulder joint. Such positioning and the application of such traction are generally shown in Pitman, et al., "The Use of Somatosensory Evoked Potentials for Detection of Neuropraxia During Shoulder Arthroscopy", Arthroscopy, Vol. 4, No. 4, 1988, pages 250-255, and in Klein, et al., "Measurement of Brachial Plexus Strain in Arthroscopy of the Shoulder", Arthroscopy, Vol. 3, No. 1, 1987, pages 45-52.
More recently, the advantages of performing shoulder procedures with the patient in the so called "Beach-Chair Position" have been covered extensively in the literature and at orthopaedic surgery congresses. For example, Stone, et al. described a procedure for acromioclavicular joint reconstruction and emphatically asserted their preference for all shoulder surgery with the patient in the beach-chair position. Furthermore, Grossfeld and Buss presented their procedure for arthroscopic evaluation of the glenohumeral joint in the beach chair position at the 1996 meeting of the American Academy of Orthopaedic Surgeons. With this way of positioning patients becoming the preference of orthopaedic surgeons, the importance of positioning devices has been raised to new levels.
Two choices exist for positioning patients in the beach-chair position, dedicated surgical tables that are factory made with the required mechanisms, and accessories to regular tables that adapt them as required. Briefly described, an operating table includes a seat support, a leg support, and a back support. The seat support extends generally horizontal for supporting the central torso of the patient. The leg support is hingedly connected to one end of the seat support. The back support is hingedly connected to the opposing end of the seat support for supporting the back and head of the patient. Normally, the three surfaces are independently adjustable by motorized or manual means and allow cushions or other attachments to be placed on them. Furthermore, operating tables are provided with a set of rails laterally connected to the adjustable surfaces, that allow attachment of accessories such as traction devices, intravenous solution bags, knee surgery rigs, etc.
Chandler, in U.S. Pat. No. 5,275,176 describes an operating table and method for shoulder arthroscopy, such table consisting of a leg support, a central support, and a back support that includes detachable modular shoulder cutouts to gain access to the posterior aspect of the shoulder. Using this device, the patient is first supported in a supine position, anesthetized, secured to the table, and the table is thereafter configured to a sitting position. One of the modular shoulder cutouts is then removed to provide access to the shoulder upon which arthroscopy is to be performed. The primary disadvantage of the Chandler device is that the operating table is factory configured with this feature. Thus, the large number of existing operating tables already in use can not be adapted to perform these procedures.
Another manufacturer, OSI of Union City, Calif. offers a shoulder positioner that adapts to operating tables. Although this device addresses the main disadvantage of the device described by Chandler, the OSI positioner limits the range of positioning from semi-seated to a reclining position of 45 degrees. The obvious disadvantage is the difficulty in transferring the patient to an operating table fitted with the OSI accessory, as such accessory does not lay in a flat position. Additionally, positioning flexibility is limited in the OSI device since it uses discrete fixed positions, as opposed to a more desirable continuous adjustment.
Another device made by AMSCO, an operating table manufacturer, attaches to the free end of the back support surface of an operating table. This configuration does not allow for continuous adjustment of the back and severely limits adjustment of the patient's lower extremities.